add taggable gem

Gemfile

@@ -28,6 +28,7 @@ gem 'delayed_job_mongoid'
 
 gem 'mongoid-tree', :git => 'git@github.com:dementrock/mongoid-tree.git', :branch => "mongoid-2.0"
 gem 'voteable_mongo', :git => 'git@github.com:dementrock/voteable_mongo.git'
+gem 'mongoid_taggable', :git => 'git@github.com:dementrock/mongoid_taggable.git'
 
 gem 'sunspot'
 gem 'sunspot_solr'

models/comment_thread.rb

@@ -3,6 +3,7 @@ require_relative 'content'
 class CommentThread < Content
   include Mongo::Voteable
   include Mongoid::Timestamps
+  include Mongoid::Taggable
 
   voteable self, :up => +1, :down => -1